Transmission Electron Microscopy Observation of Constrained Crystallization in a-Si:H/a-SiNx:H Multilayer Film

1994 ◽  
Vol 358 ◽  
Author(s):  
Xinfan Huang ◽  
Weihua Shi ◽  
Kunji Chen ◽  
Shidong Yu ◽  
Duan Feng
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Multilayer Film ◽  
Laser Annealing ◽  
Annealing Treatment ◽  
Multilayer Structures ◽  
Lattice Image ◽  
Transmission Electron ◽  
Ion Laser ◽  
Average Size

ABSTRACTThe constrained crystallization in a-Si:H/a-SiNx:H multilayer structures by Ar ion laser annealing treatment has been studied by high-resolution transmission electron microscopy (HRTEM) and Raman scattering. HRTEM photograph shows that the a-Si:H layers crystallize without disturbing the multilayer structures and that the interfaces after the crystallization are atomically smooth and uniform. The lattice image of the Si crystallites arrayed one by one can be seen clearly in Si layers and the average size is roughly equal to the thickness of Si layer. The thermodynamics of constrained crystallization within multilayer structures has been discussed.

scholarly journals Microstructure and Stability Comparison of Nanometer Period W/C, Wc/C, and Ru/C Multilayer Structures

1990 ◽  
Vol 187 ◽  
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Layered Structures ◽  
Multilayer Structures ◽  
X Ray ◽  
Transmission Electron

AbstractMultilayer structures of W/C, WC/C, and Ru/C, of various periods were prepared and studied by high-resolution transmission electron microscopy. Comparison of the phases in the layered structures is made for as-prepared and annealed samples. Both as-prepared and annealed WC/C multilayers are predominantly amorphous, while the phases in the W/C depend on the periods. The 2 nm period W/C multilayer remains amorphous after annealing, and the longer periods recrystallize to form W2C. The layered microstructures of W/C and WC/C are stable on annealing at all periods, while the amorphous Ru-rich layers in the 2 nm period Ru/C multilayer agglomerate upon annealing to form elemental hexagonal Ru crystallites. Larger period Ru/C multilayers show stable layered structures, and indicate hexagonal Ru in the Ru-rich layers. X-ray measurements show that the multilayer periods expand on annealing for all metal-carbon multilayers studied.

A New Method for Preparing Ge Nano-Crystallites Embedded in SiNY Matrices

1994 ◽  
Vol 358 ◽  
Author(s):  
Kunji Chen ◽  
Xuexuan Qu ◽  
Xinfan Huang ◽  
Zhifeng Li ◽  
Duan Feng
Keyword(s):  
Laser Annealing ◽  
Hydrogen Plasma ◽  
New Method ◽  
Transmission Electron ◽  
Scattering Spectra ◽  
Ion Laser ◽  
New Type ◽  
Raman Scattering Spectra ◽  
Average Size ◽  
20 Nm

ABSTRACTWe report a new method for synthesizing Ge nano-crystallites embedded in SiNy film matrices. On the basis of the effect of the reactant precursors and preferential chemical bonding of Si-N and Ge-Ge, thin films with Ge clusters embedded in SiNy matrices have been prepared in the PECVD system with reactant gases of SiH4, GeH4 and NH3 mixed in the hydrogen plasma. The as-deposited films were then crystallized by Ar ion laser annealing or thermal annealing technique to form nanometer-sized Ge crystallites.The composition and microstructures of these new type of sample were characterized by infrared absorption spectra, transmission electron microscopy, X-ray diffraction and Raman scattering spectra. The results indicated that the average size of Ge crystallites was estimated to be 2-20 nm depending on the deposition and annealing parameters and can be controlled by a designed manner.

Techniques for Characterising Artificial Layer Structures using Transmission Electron Microscopy

1987 ◽  
Vol 103 ◽  
Author(s):  
W. M. Stobbs
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Changes ◽  
Dark Field ◽  
Multilayer Structures ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Layer Structures ◽  
Quantitative Characterisation ◽  
Field Imaging

ABSTRACTT.E.M. methods are described for the quantitative characterisation of the compositional and structural changes at interfaces and in homo- and hetero-phase multilayer structures. Many of the newer approaches described including the Fresnel and Centre Stop Dark Field Imaging Methods were developed specifically for such characterisations. The range of applications of each of the techniques is assessed as is the importance of delineating the limiting effects of inelastic and inelastic/elastic multiple scattering.

Shock Synthesis of Nanocrystalline High -Pressure Phases in Semiconductors by High-Velocity Thermal Spray

2000 ◽  
Vol 638 ◽  
Author(s):  
R. Goswami ◽  
J. Parise ◽  
H. Herman ◽  
S. Sampath ◽  
R. Gambino ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Thermal Spray ◽  
High Velocity ◽  
Metastable Phase ◽  
High Energy ◽  
Metastable Phases ◽  
Transmission Electron ◽  
Average Size

AbstractShock synthesis of nanocrystalline Si, Ge and CdTe was accomplished using high- velocity thermal spray. Si or Ge powders were injected into a high energy flame, created by a thermal spray gun, where the particles melt and accelerate to impact on a substrate. The shock wave generated by the sudden impact of the droplets propagated through the underlying deposits, which induces a phase transition to a high pressure form. The decompression of the high-pressure phase results in the formation of several metastable phases, as evidenced by transmission electron microscopy and x-ray diffraction studies. The peak pressure is estimated to be ≈23GPa with a pulse duration of 1-5 ns. Transmission electron microscopy revealed that the metastable phases of Si with a size range of 2 to 5 nm were dispersed within Si-I. In Ge, a metastable phase, ST-12, was observed. This is a decompression product of Ge-II which possesses the β-Sn type of structure. In the case of CdTe, a fine dispersion of hexagonal CdTe particles, embedded in cubic-CdTe with an average size of 2 nm was obtained.

Modulated Structures in Ion Implanted Al-Fe System

1983 ◽  
Vol 27 ◽  
Author(s):  
K.V. Jata ◽  
D. Janoff ◽  
E.A. Starke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Purity ◽  
Annealing Treatment ◽  
Modulated Structure ◽  
Transmission Electron ◽  
Modulated Structures ◽  
Ion Energies ◽  
High Purity Aluminum ◽  
Al Matrix

ABSTRACTThe results of transmission electron microscopy studies of iron implantation into high purity aluminum foils are described. For both 50 and 100 + 50 keV incident ion energies, modulated structure has been detected in the as-implanted foils. Upon annealing at 793 K the modulated structure decomposes into the Al matrix and Al3Fe precipitates for the 50 keV implantation. A similar annealing treatment for the 100 + 50 keV implantation indicates that the modulated structure is more stable, although some Fe3Al precipitation occurs.

Structural study of Cd(S,Se) doped glasses. High-resolution transmission electron microscopy (HRTEM) assisted by image processing

1990 ◽  
Vol 23 (5) ◽  
pp. 418-423 ◽  
Author(s):  
M. Allais ◽  
M. Gandais
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Bulk Material ◽  
Optical Filters ◽  
Characteristic Size ◽  
Transmission Electron ◽  
Doped Glasses ◽  
Lattice Images ◽  
Average Size

High-resolution transmission electron microscopy (HRTEM) was used for examining Cd(S,Se) nanocrystals grown in silicate glasses commercially available as optical filters. The lattice images of the nanocrystals were numerated and submitted to filtering through Fourier transformation in order to sweep off the background signal originating mainly from glass. Optical filters from several firms were examined. The nanocrystals have been identified with Cd(S,Se) compounds crystallized in the wurzite structure, as in bulk material. The lattice images indicate crystallites having the shape of hexagonal prisms a little elongated along the c axis. The distribution of grain size differs according to the filter: the smallest size being about 1.5 nm (threshold for detection), the largest size varies from 7 to 10 nm, the average size sa , from 3–4 to 5–6 nm and the characteristic size sc from 5–6 to 7–8 nm (sc is the size of grains occupying the main part of the crystallized volume).

Tem Study of Pt Silicide Formation on Clean Si Surfaces

1983 ◽  
Vol 25 ◽  
Author(s):  
Y. Yokota ◽  
R. Matz ◽  
P.S. Ho
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Silicide Formation ◽  
Polycrystalline Structure ◽  
Epitaxial Relationship ◽  
Lattice Image ◽  
Transmission Electron ◽  
Image Technique

ABSTRACTThe microstructure of the Pt silicide formed on clean Si surfaces has been investigated using transmission electron microscopy. Pt up to 200Å was evaporated on atomically clean Si (100) and (111) substrates under an ultrahigh vacuum condition. The silicide was formed by annealing up to 600°C for (100) substrates in a purified He atmosphere and in-situ UHV for (111) substrates. For the (100) substrate, as-deposited Pt showed a fine polycrystalline structure with grain size of about 10tm. Upon annealing at 250° to 300°C, formation of Pt silicide was observed, which was primarily PtSi with only a small amount of Pt2Si. The silicide coverage was incomplete below about 1.5nm. Upon further annealing, the fraction of PtSi increased although Pt2Si persisted until 400°C. At 600°C, PtSi showed an epitaxial relationship with its c axis perpendicular to the Si (100) surface. On the Si (111) surface, PtSi formed epitaxially above 400°C. The silicide structure showed a multidiffraction pattern with three-fold symmetry, reflecting the three equivalent but strained epitaxial orientations. A high resolution lattice image technique was used to investigate the details of the epitaxial structures of PtSi on Si (100) and (111) substrates.

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